Phenylmethyl 9-(2-ethoxy-2-oxoethylidene)-3-azaspiro[5.5]undec-7-ene-3-carboxylate → HCID 22975760, compound

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Reaction Steps

9.6 g (26.0 mmol) of the protected spiro compound from Step B were dissolved in 400 ml ethanol, and the solution was filled into a hydrogenation vessel followed by 2 g Pd(II) hydroxide on charcoal. The reaction was carried out at 40° C. and 1 atm hydrogen, and it was complete after about 40 hours. The catalyst was removed by filtration through silica gel, and the filtrate was concentrated under reduced pressure. The remaining oil was treated with dry ether, filtered, and the filtrate was acidified with ethereal hydrochloric acid. The hydrochloride of the title compound was collected by filtration, washed two times with ether, dissolved in water, and the solution was made alkaline with 2 N aqueous sodium hydroxide solution. After extraction with dichloromethane the organic layer was dried over sodium sulfate and concentrated in vacuo.

Provenance & Evidence